The present invention relates to a device for selecting an operating mode of a recording and reproducing system in a tape recorder using a cassette tape.
The operation mode of the system, such as a reproducing, recording, fast-forward and rewind mode is set by operating buttons provided on an operation panel of the tape recorder. In accordance with the selected operating mode, positions of a magnetic head and a pinch roller and the rotating direction of reel gears of the system are controlled.
Japanese Utility Model Publication No. 62-32355 discloses an operating mode changing system for a cassette tape recorder where a position changing mechanism is provided for moving a head base to a predetermined position so as to change an operating mode of a cassette tape. FIG. 1 shows the system. The system comprises a chassis b provided with a pair of reel bases c.sub.1 and c.sub.2 rotatably mounted thereon to be engaged with a supply reel and a takeup reel of a magnetic tape in a cassette (not shown), respectively. A head base a having an erase head a.sub.1 and a reproduction head a.sub.2 is provided on the chassis b. The head base a has slits a.sub.3 and a.sub.4 which are slidably engaged with pins b.sub.1 and b.sub.2 secured to the chassis b. A disc cam e having a cam groove e.sub.1 is rotatably mounted on the chassis b by a shaft e.sub.2.
A supporting lever c.sub.6 is pivotally mounted on the chassis b about a pivot c.sub.5 at a central portion thereof. The lever c.sub.6 has a pinch roller c.sub.4 rotatably mounted on an end portion thereof cooperating with a capstan c.sub.3 rotatably mounted on the chassis b.
A control lever d is pivotally mounted on a pivot d.sub.1 secured to the chassis b. The lever d is provided with an engaging pin d.sub.2 at an end thereof to be engaged with a slit a.sub.5 formed on the base a, and a control pin d.sub.3 at the other end to be slidably engaged with the cam groove e.sub.1 of the disc cam e. A spring d.sub.4 is provided between the lever d and the base a so as to urge the base a in the direction shown by an arrow A.
A control lever f is pivotally mounted on a pivot f.sub.2 secured to the chassis b. The lever f is provided with a control pin f.sub.1 at an end thereof to be slidably engaged with the cam groove e.sub.1 of the disc cam e. The ever f is connected with a control plate g at the other end.
The plate g has slits g.sub.1 and g.sub.2 to be slidably engaged with pins b.sub.3 and b.sub.4 secured to the chassis b so that the plate is moved in the direction shown by an arrow B in accordance with the lever f. The plate g is provided with a flange portion g.sub.3 having a notch g.sub.4. The notch g.sub.4 is adapted to be engaged with the lever c.sub.6 at the other end portion. A spring g.sub.6 is provided between a projection g.sub.5 of the plate g and the lever c.sub.6 so as to urge the lever c.sub.6 in the counterclockwise direction about the pivot c.sub.5.
The head base a and the control plate g are moved by the operation of the levers d and f in dependency on the configuration of the cam groove e.sub.1 for controlling the positions of the heads c.sub.1 and c.sub.2 and the pinch roller c.sub.4.
The system of FIG. 1 shows a position in stop, rewind and fast-forward modes. The head base a is located at a retracted position so that heads a.sub.1 and a.sub.2 are disengaged from the tape. The end of the supporting lever c.sub.6 is engaged with the notch g.sub.4 of the plate g so that the pinch roller c.sub.4 is separated from the capstan c.sub.3. In cue, pause and play modes, the base a is moved in the direction A. Thus, the heads c.sub.1 and c.sub.2 are engaged with the tape and the lever c.sub.6 is disengaged from the notch g.sub.4 so that the lever c.sub.6 is rotated in the counterclockwise direction by the spring g.sub.6. The pinch roller c.sub.4 is abutted on the capstan c.sub.3 so that the tape is transmitted passing between the capstan and pinch roller.
In the system, a rotating power of the disc cam e is transmitted to the head base a and the supporting lever c.sub.6 with control levers d and f for moving the base plate and pivoting the supporting lever. Therefore, the system is complicated in construction. It is difficult to reduce the size of a car stereo or a portable tape recorder where a number of parts are assembled in a smaller space. Furthermore, the rotating power of the disc cam e is not efficiently transmitted to the base a and lever c.sub.6 because there is a power loss in the transmitting structure.
In fast-forward and rewind modes, in order to rotate the reel bases c.sub.1 and c.sub.2 at a high speed, it is necessary to change the engagement of the gears by an idler gear. A mechanism for changing the position of the idler gear corresponding to the base is provided independent of the position changing mechanism of the base. Accordingly, the structure is further complicated, and it is necessary to set a timing for operating both mechanisms.